Consider a reaction:$$\ce{$aA + bB$ <=> $cC + dD$}$$ The value of reaction quotient at a certain time $t$, $${Q_c = \frac{[C]^c[D]^d}{[A]^a[B]^b}}$$ where the concentrations $[A], [B], [C]$ and $[D]$ are at time $t$. Let the reaction start initially at $t = 0$, with only reactants $i.e.$ $[A]$ and $[B]$ equal to say $1$ mol […]

- Tags [C]$ and $[D]$ are at time $t$. Let the reaction start initially at $t = 0$, $${Q_c = \frac{[C]^c[D]^d}{[A]^a[B]^b}}$$ where the concentrations $[A], $$K_c > 0$$ Thus, $$Q_c < K_c$$ Which is the only condition for the advancement of reaction in forward direction. This condition does not consider the value of, $$Q_c = 0$$ We know that the value of equilibrium constant $K_c$ must be such that, B, can it be concluded that every reaction is spontaneous in forward direction if it starts with only reactants? If so, Consider a reaction:$$\ce{$aA + bB$ $cC + dD$}$$ The value of reaction quotient at a certain time $t$, considering the relation $$\Delta G = \Delta G^o + RT~\mathrm{ln}~Q_c$$ When $Q_c = 0+$ then $\mathrm{ln}~Q_c \to -\infty$, how can we define a non-spontaneous reaction?, which means $\Delta G << 0$ and reaction is spontaneous in forward direction. Hence, with only reactants $i.e.$ $[A]$ and $[B]$ equal to say $1$ mol and $[C]$ and $[D]$ equal to $0$ mol. Hence